In the coming months, parts of southern Africa may experience the worst flooding in the last 20 or 30 years. That’s the warning Monday from the U.N. Food and Agriculture Organization (FAO).

It says the La Nina weather phenomenon has brought heavier than normal rainfall, destroying thousands of hectares of agricultural land and crops so far. The seasonal rainy season is only half over and the cyclone season is expected to peak this month.

“We are just right in the middle of the cropping season in many of these countries. So the impact of the flood damage can be very high in terms of the future harvest,” he says. It’s possible, he adds, that the entire season’s harvest could be lost.

The FAO is conducting an assessment of the region and is expected to have a new estimate on crop damage next week. “It seems that we are just at the beginning of the problem,” says Scaglia.

While the damage assessment is still underway, the FAO official says preliminary figures can paint a picture of what’s happening.

“It’s something quite worrying,” he says, “For example, in Lesotho, it’s a bit vague but we think that probably between 20 and 40 percent of the planted area may be affected. And we also have figures very similar in other countries, which will be confirmed in the coming days.”

La Nina

The U.S. National Oceanic and Atmosphere Administration (NOAA) says La Nina is characterized by unusually cold ocean temperatures in parts of the world.

Scaglia says, “You had an extremely high level of rainfall, for example, last week. It could be one or two days. [They] really got what they usually get in a month. So it is at this level. And we know that it is connected to the La Nina phenomenon. Right now, [it’s] extremely active in all of southern Africa, East Africa and the Indian Ocean."

While heavy rains can create floods by themselves, they also cause rivers to overflow their banks.

“Definitely,’ he says, “we have to try to control animal disease. You have floods – immediately it means animal disease will be increasingly an issue for the farming community.”

As the result, disease surveillance and animal vaccination programs are in effect.

“On the crop side, it’s a little more difficult right now," he said. "Unfortunately, we may have to wait until the end of the floods to really try to see what we can do. What should be done in the coming months will be to rebuild the seed stock, which will be completely depleted. It’s a very traditional operation.”

The FAO says, “South Africa has already declared a national state of disaster in many districts of the country due to the floods.” Crop and land damage is estimated to be in the millions of dollars.